Field
The present disclosure relates to a display device having a touch sensor.
Discussion of the Related Art
Development of multimedia has led to an increase in demand of display devices able to appropriately display the multimedia. In order to meet the increase in demand, flat display devices (or display devices) which are increased in size and low-priced, and have high display quality (video expression, resolution, brightness, contrast, and color reproducibility, and the like) have been actively developed. In these flat display devices, various input devices such as a keyboard, a mouse, a track ball, a joystick, a digitizer, and the like, are used to form an interface between users and the flat display devices. However, the use of the aforementioned input devices requires users to learn how to use the input devices and inconveniences as the users with installation of the input devices and occupation of the input devices of an operation space, making it difficult to increase completeness of products. Thus, demand for input devices which are convenient to use, simple, and reduce malfunction has grown. In order to meet the demand, touch sensors capable of recognizing information generated as users directly touch a screen with their hands or a pen or apply a touch in a proximity manner, while viewing a display device, has been proposed.
A touch sensor used in a display device may also be implemented in an in-cell type touch sensor installed within a display panel. An in-cell type display device may employ a scheme in which a touch electrode of a touch sensor and a common electrode of a display panel are shared and driving is performed by time division of a display period and a touch sensing period. In particular, a display panel may be divided into a first block PB1 and a second block PB2 as illustrated in Figure (FIG. 1, and display driving and touch sensing driving may be performed in units of the divided blocks. For example, after data of an input image is written into pixels of the first block PB1 during a first display period Td1, touch sensors are driven to sense a touch input during a first touch sensing period Tt1. Subsequently, after data of an input image is written into pixels of the second block PB2 during a second display period Td2, touch sensors are driven to sense a touch input during the second touch sensing period Tt2.
During the display period, a gate driver sequentially shifts a gate pulse applied to gate lines using a shift register. A gate pulse is synchronized with the data signal of the input image and sequentially selects pixels in which the data signal is to be charged, one line each time. The shift register of the gate driver includes dependently connected stages. The stages of the shift register are dependently connected to receive a start pulse and/or an output of a previous stage to charge a node (e.g., a Q node). When the display period is not divided but continuous, node charge periods (e.g., Q node charge periods) (hereinafter, referred to as “a standby period”) of all the stages of the shift register are the same as approximately 2 horizontal periods.
However, when the display period is divided in units of the blocks (e.g., Td1 and Td2) as illustrated in FIG. 2, and a touch sensing period is allocated there between (e.g., Tt1 and Tt2), and a Q node of a stage generating a first output immediately after the touch sensing period is decayed by the touch sensing period to generate a low output. In case of full high definition (FHD), 1 horizontal period is approximately 6.0 μs and a touch sensing period is 100 μs or longer. Thus, a standby period of a stage generating a first output immediately after the touch sensing period is 100 μs or longer, while a standby period of other stages is about 12.0 μs. Since the standby period is lengthened, a decay time of a node is lengthened, causing a line dim phenomenon at a first line from which the display period starts again immediately after the touch sensing period.